different problems on a .40 S&W.....kinda long but might help another.

[mozeppa]

before it was getting answers to problems with store bought bullets....now i'm using 180 grain BOOLITS that are powder coated.

personal note : i'am VERY meticulous when it comes to observances and measurements.

so here is what i know to be fact:

180 grain (wheel weight alloy) boolit....no lube grooves ...1 ogive with a flat meplat....beveled base and sized to 0.4015".

cases are used "win" cases sized, cleaned & re-primed with WSP primers, belled and chamfered.
all cases are 0.836" long on average. saami says max is 0.850 bu i have rarely ever seen a case that measures any longer than 0.840 ...i never trim them and don't anyone who does....saami also states a minimum O.A. L. of 1.085" to a max of 1.135" I tried 3 sizes of 1.120"---1.125"---1.130" with the same results.

my barrel IS throated and i'm positive that my crimp is minimal and the BOOLIT in no way makes any contact with the lands and grooves of the bore when in full battery.

when they do fire it is very accurate (dime size group of 3) off hand at 20 feet...(shot thru a chrony at just above 1000 FPS)
and it will fire the first 5 or 6 rounds perfectly.....however!after 6 rounds the chamber is so fouled that any rounds after that must have the slide physically pushed forward to fire it again ....and so on.

i'm using 7.0 grains AA#5 powder for 1000 to 1015 FPS


when it doesn't fire it is because the slide has NOT fully closed....about 1/8th inch.

so i measured the barrel and chamber .....here what i noted....

the diameter of the head space ledge = exactly 0.4243"
the diameter at the web = exactly 0.4273"
bore = 0.3895" on the lands and 0.4005" in the grooves.

so then i checked SAAMI specs.....and if i'm reading the schematic right, then this barrel is cut on the very minimum size that SAAMI states.

SAAMI also states in a box that i put a red square around this bit of info...."chamber unless otherwise noted all Dia. +0.004"
Does this mean that my chamber could be as much as 0.4283" at the case mouth?....and 0.4313 at the web? ....and still
be within SAAMI specs.? ...it also says "length tolerances +0.015".... which means it could chamber a 0.850 case properly....but that not the problem

again ...my problem is it gets too grungy in the chamber to push in another cartridge into full battery.

my thoughts were at first getting a stronger recoil spring ....but i dismissed that as it does nothing about the dirt.

then i remembered that "Glocks" are somewhat known to have a "more generous" sized chamber (i don't mean the un-supported part.)

i am of the idea that my chamber is just too tight and any grunge at all is just too much to make it cycle.

i've picture the SAAMI Spec. sheet below from their website.....and made a drawing of mine as well.

am i thinking right?....ream out the chamber couple thousandths? ......whats the worst that could happen?...buy a new barrel?

[popper]

Plunk test all you rounds in the bare barrel. IMHO the boolit is truncated cone BB design and just a few thou. of the drive band hitting the throat will cause a jam. You can also get case bulges due to difference in case wall thickness. I also get a few from taper crimp 'mushing' some alloy over the mouth rim. My XD has never given the dreaded lead ring in the throat.
If you chamber is really on the tight side, you need to size smaller. No, stronger spring most likely won't help.

[Dusty Bannister]

A good start would be to plunk test all cartridges to see if there is any thing related to powder coating that prevents chambering. I would also suggest that you use the dowel method to determine the cartridge OAL that will chamber easily. If you are not familiar with that, send a PM and I will reply. Does the completed bullet pass the smash test? You mention "dirt" so is that lead or PC material and powder residue? And the bullets are sized AFTER powder coating? It sort of sounds like the bullet is seated a little too short and when the primer is ignited, the hot gasses are blowing some of the coating ahead of the bullet where it is deposited ahead of the case where it fouls the chamber. No mention of fouling being blown back along the case body, but you might watch for that as well.

Perhaps after you get the correct cartridge OAL the rest of the issues will resolve. Did you start from the suggested starting load, or are you trying to reach major without working up the load?

[cwlongshot]

I shoot ALLOT of cast powder coated thru my 40’s.

Most of my “steel” loads are med loads of Power Pistol powder in mixed cases. Heavier loads get like cases and full house get new brass. (Like head stamped of coarse)

Im able to shoot .402 sized in glock barrels but only 401 thry my Lone Wolf or KKM. My Silencer-co barrel dosent reliably like ANY cast. Ooh it shoots plenty accurate, but will not reliably cycle any combination I have tried.

What Im telling ya is all barrels are different. Yes generally factory barrels are more generious. But not always ESP when looking at Gen 5 stuff.

Good taper crimp goes a long way to reliably feeding with cast. Heck some FACTORY needs to be run thru my taper crimp to “run” reliable!!

I always size after PC.

CW

[mozeppa]

i knew i forgot to list something....YES! i "plunk test" every single cartridge....and yes , they go "plunk" in the clean barrel.
in my drawing i list the maximum size for my brass that i use...(in fact most of my brass sizes to a smaller size than listed ....more like 0.4225 at the web and 0.4205 at the case mouth. what is being missed by the thread respondents is that the gun functions perfectly for the first 5 or 6 shots... then it's too dirty to go into full battery and the slide hangs slightly to the rear....if i clean the barrel, then i'm good for 5 or 6 more shots with no hiccups. then it hangs again.

it's not magazine trouble either... i have 16 Wilson combat mags ...all relatively new.

7 grains of AA#5 is not a all out speed demon....barely over 1000 FPS...(average 982 to 1010 by my chrony)

i size after powder coat to 0.4015....

i do use a taper crimp and i don't get any loose boolits or jump or setback.
i'm not getting any "mush" of powder coat or lead at the case mouth either, one of the first things i looked for.

in my mind i'm almost convinced that the powder produces too much soot and upon ejection the soot coats the chamber wall....couple that with an already tight
size of chamber and after 6 shots the darn thing is too tight to feed another.

i'm hoping someone will chime in that has a more generous size chamber dia. and can help figure this out.

again....am i reading the SAAMI specs. right? can the chamber size be as much as 0.431+ at the web and 0.428+ at the case mouth?

[country gent]

At you loading level the aa5 may have a couple issues one not enough pressure to seal case to chamber and it may not be burning cleanly at the lowered pressures. A slight increase in crimp my help with the burning cleaner. A mid point taper crimp may provide enough added resistance to get the cleaner burn

[mozeppa]

how about more powder to get more pressure?

move the speed up to about 1300 FPS?.......... as well as the added crimp.

and how do you achieve a "mid point taper crimp"?

[44MAG#1]

I would say if you moved the velocity of a 40 S&W with a 180 gr bullet to 1300 FPS you would have a REAL load.

how about more powder to get more pressure?

move the speed up to about 1300 FPS?.......... as well as the added crimp.

and how do you achieve a "mid point taper crimp"?

[onelight]

When you eject a loaded round does the bullet have any marks on the ogive from contact with the throat ?
Does it require normal effort to work the slide when ejecting it ?

[mozeppa]

9th line down in first post....

my barrel IS throated and i'm positive that my crimp is minimal and the BOOLIT in no way makes any contact with the lands and grooves of the bore when in full battery.

yes ...normal slide operation to eject a live round.

[cwlongshot]

Easily done... Simply a 16” barrel.

CW

[Dan Cash]

I agree with Country Gent in that I think your propellant is too dirty and not reaching an optimum combustion pressure. I would try a faster powder like Bulls Eye for the velocity level you are using.

[popper]

Try unique or 231. Those slow powders are dirty. Cfe pistol is the same way, real dirty. Faster powder will seal the case.

[onelight]

Interesting problem .
I look forward to your solving the mystery.

[mozeppa]

i have unique and bullseye ...will try each this weekend and report back.

[W.R.Buchanan]

My standard load of 5.4 gr of W231 seals the cases perfectly in both of my Glocks G23 and G35 and my My Ruger PCC .40 carbine. This si with 165 gr plated boolits.

I am about to start using PC'd Lee 175 gr. boolits in mine. The Bevel Base can be a problem in non PC'd boolits as it promotes blow by. With the PC it is a non issue.

Change your powder. The AA5 would be fine in my Rifle and get higher Velocities but that load would be specific to rifles and wouldn't cross over very well.

Randy

[onelight]

I have had good results with Alliant BE- 86 in 40 and several other cartridges to.

[mozeppa]

my observations at this point made me suspect that aa#5 was too dirty a burn and too slow a burn as the case was being ejected most of the gas was vented
out the muzzle...BUT! a significant amount of the gas was being vented into the chamber as well (enough to coat the chamber in soot)
also might be the reason the empties were dropping at my right foot...in other words ...not enough "pop" to fling the cases 6 or 7 feet behind me.

i totally missed 2 things that the guys here pointed out!....(you guys are a wealth of knowledge and ideas!....much gratitude here!...thanks!

1. has to be enough "pop" to obturate the lead boolit to help seal the gas behind the boolit
2. and working hand in hand ...that "pop" has to be enough to help seal the case in the chamber!

(one of my observations noted was that i could clean the barrel thoroughly and take any of the fired brass and put in in the chamber VERY easily....like
it wasn't expanded tight enough .....it SHOULD have been much tighter than almost literally "plunk" testing the empty fired brass!)




initially i was fooled by the bullet speed of 1000+/- FPS ....it was what was happening after the bullet was on the move.

also was fooled by the loading manuals that list AA#5 as a powder for 175/180 grain lead boolits...while it "works" in auto's ....i and perhaps some others
would be cleaning the barrels after 7 shots.

will be loading more test rounds tonight for tomorrows testing....will update then.

[mozeppa]

still yet has anyone have an answer for my question on whether or not i am interpreting the SAAMI spec sheet in my first post correctly?

SAAMI states in a box that i put a red square around this bit of info...."chamber unless otherwise noted all Dia. +0.004"
Does this mean that my chamber could be as much as 0.4283" at the case mouth?....and 0.4313 at the web? ....and still
be within SAAMI specs.?

any design engineers here?.....gun smiths?...tool makers?

[mozeppa]

shot off the test loads using bullseye powder ...much better results.

4.9 grains bullseye cycles the gun just fine and i fired 36 rounds without a fail... chrony checks out 14 shots at 1005 FPS as a low, and 1034 as a high
with the average right at 1020 FPS.

still burns a little dirty ...but not like aa#5

AA#5 on the burn chart is number 41 ............and bullseye is number 13

red dot is number 8 ...so... if red dot is a slightly faster burn ... i wonder if i can work up a load using red dot in hopes of burning cleaner yet (hoping to do mostly away with so much soot)?

anyone using red dot in a .40 S&W?.........i ask because i'm 24 pounds of red dot to the good!